ABSTRACT
[Abstract] Objective To discuss the effect and the corresponding mechanism of transforming growth factor β1 (TGF-β1) in promoting the bronchial epithelia synthesis and the expression of thymic stromal lymphopoietin (TSLP), so seek out a potential therapeutic target for asthma. Methods Human bronchial epithelia cells (HBEc) were cultured in vitro, and then divided into 0h group, 3h group, 6h group, 12h group, 24h group and 48h group to evaluate the effect of TGF-β1 stimulation in different time points; and divided into 0ng/ml group, 0.1ng/ml group, 1ng/ml group and 10ng/ml group to evaluate the effect of TGF-β1 stimulation in different concentrations. SB431542, a TGF-β1 antagonist, was used to block the effect of TGF-β1, HBEc were divided into negative control group, TGF-β1 group (1ng/ml TGF-β1) and TGF-β1+SB431542 group (1ng/ml TGF-β1+10μmol/L SB431542). Western blotting was performed to detect the protein expression level of TSLP, p-Smad3 and Smad3, while qRT-PCR was performed to determine the mRNA transcription level of TSLP. Concentrations of TSLP in HBEc culture supernatants were measured by ELISA. Results As the co-culture time with TGF-β1 prolonged, the expression of TSLP in HBEc increased. The relative expression of TSLP protein was significantly higher in 24h group (0.803±0.022) than in 0h group (0.350±0.032, P<0.05), and the relative expression of TSLP mRNA also increased (4.957±0.391 vs. 1.002±0.086, P<0.05). The levels of TSLP mRNA transcription and protein expression were significantly higher in 1ng/ml TGF-β1 group (7.954±2.004; 1.522±0.003) than in 0ng/ml TGF-β1 group (1.008±0.152; 0.758±0.014, P<0.05). The concentrations of TSLP in HBEc culture supernatants were markedly higher in 1ng/ml TGF-β1 group than in 0ng/ml TGF-β1 group (160.157±7.050 vs. 138.817±1.940, P<0.05). The ratio of p-Smad3/Smad3 declined obviously in TGF-β1+SB431542 group than in TGF-β1 group (0.808±0.063 vs. 1.116±0.049, P<0.05). Meanwhile, the relative expression of TSLP protein was significantly lower in TGF-β1+SB431542 group than in TGF-β1 group (1.016±0.030 vs. 1.186±0.045, P<0.05). Conclusion TGF-β1 may induce the expression of TSLP in HBEc by up-regulating Smad3 phosphorylation, which may be a novel method in curing asthma.